| electron paramagnetic resonance [i`lek´trän ¦par·ǝ·mag¦ned·ik `rez·ǝn·ǝns] PHYSICS Magnetic resonance arising from the magnetic moment of unpaired electrons in a paramagnetic substance or in a paramagnetic center in a diamagnetic substance. Abbreviated EPR. Also known as electron spin resonance (ESR); paramagnetic resonance. |